The pan-European Stoxx 600slipped lower, down 0.38 percent, and major bourses closed in mixed territory.

The euro jumped as high as $1.1655 after ECB President Mario Draghi pointed to plans for policymakers to begin discussing a gradual wind down of its quantitative easing (QE) program in the fall.

The FTSE 100 benefited from the fall in the price of sterling against the euro but the French CAC and the German DAX suffered from the trade.

European stocks fell largely into negative territory Thursday following the ECB's announcements and after several companies reported earnings for the second quarter of the year.

Finnish ship technology and power plant maker Wartsila surged towards the top of the benchmark after better-than-expected earnings. The firm said it surpassed analyst's projections on improving market demand for its marine solution business. Its shares soared over 7 percent to hit an all-time high during morning trade before falling back to around 4.4percent higher by the close of play.

Unilever reported marginally weaker-than-expected quarterly sales on Thursday, as the firm looked to recover from the fallout of a spurned $143 billion takeover bid earlier this year. Its shares were up 1.7 percent when markets closed.

Price comparison platform Moneysupermarket slumped close to the bottom of the benchmark on Thursday morning after it reported earnings for the first half of 2017. While the group posted a 3 percent rise in adjusted operating profit, Moneysupermarket warned investors it would likely be at the lower end of market consensus by year-end due to current trends in energy trading. By closing deals it was trading down 2.5 percent.

Lufthansa filled the spot at the bottom of the benchmark, down 8.5 percent. It announced Wednesday that it would be expanding its European network this winter.

ECB leaves rates on hold

While the central bank's decision to hold interest rates was widely expected, the ECB also reiterated its pledge to continue buying 60 billion euros ($68.8 billion) of new bonds each month until the end of 2017.

Meanwhile, the second round of formal Brexit talks concluded on Thursday as negotiators from the EU and the U.K. meet in Brussels.

Earlier in the trading day, the Bank of Japan kept its monetary policy unchanged after its two-day meeting. However, the central bank slashed its inflation forecasts for fiscal years 2017/2018 and 2018/2019.

U.S. stocks were mixed Thursday. On Wednesday they closed at record highs as investors digested better-than-expected earnings.